package com.sun.xacml.combine;

import java.net.URI;
import java.net.URISyntaxException;
import java.util.Iterator;
import java.util.List;

import com.sun.xacml.EvaluationCtx;
import com.sun.xacml.Rule;
import com.sun.xacml.ctx.Result;

public class ANDRuleAlg extends RuleCombiningAlgorithm{

	public static final String algId =
        "urn:ogc:def:function:geoxacml:1.0:rule-combining-algorithm:" +
        "and";

    // a URI form of the identifier
    private static URI identifierURI;
    // exception if the URI was invalid, which should never be a problem
    private static RuntimeException earlyException;

    static {
        try {
            identifierURI = new URI(algId);
        } catch (URISyntaxException se) {
            earlyException = new IllegalArgumentException();
            earlyException.initCause(se);
        }
    }
	
	public ANDRuleAlg() {
		super(identifierURI);

        if (earlyException != null)
            throw earlyException;
	}
	public ANDRuleAlg(URI identifier) {
		super(identifierURI);
	}
	@Override
	public Result combine(EvaluationCtx context, List rules) {
		// TODO Auto-generated method stub
		boolean atLeastOneNotApplicable = false;
		boolean atLeastOneError = false;
        boolean potentialDeny = false;
        boolean potentialPermit = false;
        boolean atLeastOnePermit = false;
        boolean atLeastOneDeny = false;
        Result firstIndeterminateResult = null;
        Iterator it = rules.iterator();

        while (it.hasNext()) {
            Rule rule = (Rule)(it.next());
            Result result = rule.evaluate(context);
            int value = result.getDecision();
            
            // if there was a value of DENY, then regardless of what else
            // we've seen, we always return DENY
            
            
            // if it was INDETERMINATE, then we couldn't figure something
            // out, so we keep track of these cases...
            if (value == Result.DECISION_INDETERMINATE) {
                atLeastOneError = true;
                
                // there are no rules about what to do if multiple cases
                // cause errors, so we'll just return the first one
                if (firstIndeterminateResult == null)
                    firstIndeterminateResult = result;

                // if the Rule's effect is DENY, then we can't let this
                // alg return PERMIT, since this Rule might have denied
                // if it could do its stuff
                if (rule.getEffect() == Result.DECISION_DENY)
                	potentialDeny = true;
                
                // if the Rule's effect is DENY, then we can't let this
                // alg return PERMIT, since this Rule might have denied
                // if it could do its stuff
                if (rule.getEffect() == Result.DECISION_PERMIT)
                	potentialPermit = true;
            }
            
            if(value == Result.DECISION_NOT_APPLICABLE)
            {
            	 return new Result(Result.DECISION_NOT_APPLICABLE,
                         context.getResourceId().encode());
            }
            if (value == Result.DECISION_DENY)
            {
            	atLeastOneDeny = true;
            	
            } else {
                // keep track of whether we had at least one rule that
                // actually pertained to the request
                if (value == Result.DECISION_PERMIT)
                    atLeastOnePermit = true;
            }
        }
        System.out.println("atLeastOneDeny = " + atLeastOneDeny );
        System.out.println("atLeastOnePermit = " + atLeastOnePermit );
        // we didn't explicitly DENY, but we might have had some Rule
        // been evaluated, so we have to return INDETERMINATE
        if (potentialDeny || potentialPermit)
        	return firstIndeterminateResult;
        
        // there are at least 2 rule return permit and deny, so just return interminate
        if (atLeastOnePermit && atLeastOneDeny )
        {
        	System.out.println("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
            return new Result(Result.DECISION_INDETERMINATE,
                              context.getResourceId().encode());
        }
        
        // we return PERMIT because there no deny and no not applicable, no errors and at least one permit
        if(atLeastOnePermit)
        {
        	return new Result(Result.DECISION_PERMIT,
                    context.getResourceId().encode());
        }
     // we return DENY because there no deny and no not applicable, no errors and atleast one deny
        if(atLeastOneDeny )
        {
        	return new Result(Result.DECISION_DENY,
                    context.getResourceId().encode());
        }
        
        
        	 
       
        // problem with one of the Rules, then we're INDETERMINATE
        if (atLeastOneError)
            return firstIndeterminateResult;
        
        // if we hit this point, then none of the rules actually applied
        // to us, so we return NOT_APPLICABLE
        return new Result(Result.DECISION_NOT_APPLICABLE,
                          context.getResourceId().encode());
    }
	

}
